The work in progress deals with the development of a porous surface material coating for use with chrome cobalt molybedenum subperiosteal implants. This effort includes adhesion testing of polished metal surfaces and surfaces that were sandblasted. The effects of silane coupling agents on adhesion bond strength are under investigation. A major thrust of this study involves experiments that demonstrate the importance of surface treatment on the ultimate tissue reaction to the implant. We have identified deficiencies in the standard methodology for casting and finishing implant that leave an "unclean" surface. These organic and inorganic contaminants alter tissue response adversely. Experiments have been designed to study the effects of implant treatment with glow discharge which provides a sterile maximum surface energy interface. Of special significance is the utilization of surface chemical and physical methods to measure surface free energy. The characterization of tissue reaction to an elastomeric surface and a metallic surface of optimum surface energy is the ultimate objective of these experiments. This information will be compared against the base line data obtained from the first three years of the experiment which dealt with 40 unilateral subperiosteal implants. Special attention is directed to the effect of surface energy and porous coating on certain phenomena such as persistant ulceration along the implant post, epithelial migration and chromic inflammation deep within the implant crypt.